Foulard for applying a binder to a gauze

ABSTRACT

In a foulard for applying a binder to a gauze, fleece or preliminary fleece, having at least one first roll, which can be rotated about a first roll axis and has an engraved roll sleeve, at least one second roll, which can be rotated about a second roll axis and has a roll sleeve, and wherein the gauze, the fleece or the preliminary fleece runs between the first and second rolls, the roll sleeve of the second roll has a preferably groove-shaped engraving.

The invention relates to a foulard for applying a binder to a gauze, nonwoven or preliminary nonwoven according to the precharacterizing part of claim 1, as well as to a method for applying a binder to a gauze, nonwoven or a preliminary nonwoven according to claim 12.

Devices and methods for producing nonwoven fabrics are known, in which a gauze, nonwoven or preliminary nonwoven in the form of a material web is passed through a foulard, with a binder being introduced into the gauze, non-woven or preliminary nonwoven. Downstream of the foulard, the nonwoven or gauze provided with the binder is most often fed to an oven in which the binder is activated by heat.

Known foulards for applying a binder to a gauze, nonwoven or preliminary non-woven comprise at least one first roll rotatable around a first roll axis, the roll having an engraved roll sleeve. Further, at least one second roll is provided, which is rotatable around a second roll axis and has a roll sleeve, the roll sleeve of the second roll being smooth.

Up to the present, there exists the drawback that such nonwovens cannot be passed through such a foulard at a high velocity, since, in such a case, the non-woven would stick on a roll.

Thus, it is an object of the present invention to provide a foulard and a method for applying a binder to a nonwoven, in which such a nonwoven can be passed through the foulard at a high velocity.

The object is achieved with the features of claim 1 and claim 12.

The invention advantageously provides that the roll sleeve of the second roll has at least one engraving.

This is advantageous in that the nonwoven does not stick on the second roll so that the foulard can be operated at higher velocities.

The engraving in the roll sleeve of the second roll may be a groove-shaped engraving, preferably a spiral-shaped engraving. For example, a groove may be formed in a spiral shape as an indentation in the entire roll sleeve of the second roll. As an alternative, a plurality of groves arranged side by side may be provided in the roll sleeve of the second roll, the grooves extending preferably in the direction of the circumference.

The dimensions of the at least one, preferably groove-shaped engraving in the roll sleeve of the second sleeve can be such that the volume of the preferably groove-shaped engraving is larger than the overall volume of the gauze, non-woven or preliminary nonwoven, consisting of fibers, which in operation passes between the first and second roll per rotation of the second roll. This has the advantage that the volume of fibers of the gauze, nonwoven or a preliminary non-woven present in the nip in operation, i.e. in the region between the first and second roll, is smaller than the volume of the part of the engraving that is in the nip region. This means that the fibers of the gauze, nonwoven or preliminary nonwoven in the nip can escape into the preferably groove-shapes engraving and that no piling up of fibers of the gauze, nonwoven or preliminary nonwoven and of the binder occurs.

The dimensions of the at least one preferably groove-shaped engraving in the roll sleeve of the second roll can be such that the volume of the preferably groove-shaped engraving, which is present in the working width region, is larger than the overall volume of the gauze, nonwoven or preliminary nonwoven, consisting of fibers, which in operation passes between the first and second roll per rotation of the second roll. The working width of the first and/or second roll is the width of the gauze, nonwoven or preliminary nonwoven passing between the first and second rolls.

The dimensions of the at least one preferably groove-shaped engraving can be such that the open area of the roll sleeve surface of the second roll preferably is between 60 and 98%, in particular between 80 and 85%.

The width of the groove or the grooves of the first and/or the second roll in the plane of the surface of the respective roll sleeve is preferably between 0.1 mm and 2 mm, preferably between 0.4 and 1.5 mm, in particular 1 mm. The web or the webs between the groove or the grooves of the first and/or the second roll in the plane of the surface of the respective roll sleeve preferably is between 0.1 mm and 2 mm, preferably between 0.4 and 1.5 mm, preferably 1 mm.

The width of the groove or the grooves of the first and/or the second roll preferably tapers in the radial direction. The cross-sectional shape of the groove or the grooves of the first and/or the second roll can be conical, frustoconical or notch-shaped.

The roll sleeve of the second roll can be made of synthetic material, preferably rubber. Alternatively, the roll sleeve can be made of metal. The engraving can be milled or turned into the roll sleeve.

The engraving in the roll sleeve of the first roll can be a groove-shaped, preferably a spiral-shaped engraving.

The engraving in the roll sleeve of the first roll has the advantage that in a liquid foulard, on the one hand, the binder can be applied to the nonwoven with the first roll and, on the other hand, excess binder can be drained via the engraving.

The roll sleeve of the first roll can be made of metal, preferably stainless steel.

The first roll can be arranged such that the roll sleeve of the first roll plunges at least partly into a trough filled with a liquid binder, so that the liquid binder can be applied to the nonwoven or the gauze by means of the first roll. In this case, the foulard is a liquid foulard.

In addition, a stripping means can be provided which allows to control the amount of binder to be applied to the nonwoven.

The first and the second roll axis of the first and the second roll can be arranged substantially vertically above one another.

The first and the second roll axis of the first and the second roll can be arranged substantially horizontally one beside the other.

Further, according to the invention, it is advantageously provided to provide a method for applying a binder for a gauze, nonwoven or preliminary nonwoven, which includes the following steps:

-   -   feeding a gauze, nonwoven or preliminary nonwoven to a foulard         having a first and a second roll, the roll sleeves of the first         and the second roll respectively comprising an engraving,     -   applying the binder to the gauze, nonwoven or preliminary         non-woven,     -   passing the gauze, nonwoven or preliminary nonwoven through the         first and the second roll, applying pressure on the gauze,         nonwoven or preliminary nonwoven via the roll sleeves of the         rolls.

A liquid binder can be applied to the gauze, nonwoven or preliminary nonwoven.

As an alternative, a binder dissolved in foam can be applied.

Referring to the drawings, embodiments will be explained in detail hereunder.

THE FIGURES SCHEMATICALLY SHOW

FIG. 1 a device for producing a nonwoven fabric with a foulard,

FIG. 2 a side elevational view of the foulard in FIG. 1,

FIG. 3 a cross section through the foulard in FIG. 2,

FIG. 4 a device for producing a nonwoven fabric with a foam foulard,

FIG. 5 a detail of the roll sleeve of the second roll,

FIGS. 6 a-6 c different shapes of cross sections of groove-shaped engraving provided in the roll sleeve of the second roll.

FIG. 1 shows a device for producing a nonwoven fabric. A gauze 14 is produced in a gauze producing device 16, which may be a carding machine or a spunbonded fabric layer, for example. This gauze 14 is laid on a band screen 23. The band screen 23 is guided around guide rollers 22, at least one of the guide rollers being driven, so that the band screen 23 runs around these guide rollers 22. The circulating band screen 23 transports the gauze 14 in the conveying direction 26 to a foulard 1.

As an alternative, it is also possible to arrange a hydroentanglement device, not illustrated herein, upstream of the foulard 1 in the conveying direction 26, thereby allowing the gauze 14 to be precompacted by means of this hydroentanglement device.

As another alternative, it is possible to provide a compacting drum or compacting roll, not illustrated herein, upstream of the foulard 1 in the conveying direction 26 to thereby compact the gauze 14.

FIG. 1 shows a liquid foulard. The liquid binder 30 is provided in a trough 28. The binder 30 is applied to the gauze 14 by means of the first roll 4. This is effected by arranging the first roll 4 such that the roll sleeve of the first roll dives into the liquid binder provided in the trough 28, and by applying the binder to the gauze 14 by means of the roll sleeve 8 of the first roll 4.

The gauze 14 passes between the first and the second roll 4, 2, i.e. in the nip between the first and the second roll 4, 2, in which the fibers of the gauze and the binder 30 are present between the first and the second rolls 4, 2. Pressure is applied on the gauze 14 via the roll sleeve 8 of the first roll 4 and the roll sleeve 6 of the second roll 2, whereby the binder 30 spreads in the gauze 14 in the nip.

The gauze 12, to which binder has been applied, is fed to a drier or oven 24 after having passed the foulard. In this oven 24, the binder is activated by means of heat, and a compacted nonwoven fabric is obtained.

Thereafter, the nonwoven fabric can, e.g., be wound on a roll, not illustrated herein, or it can be processed directly.

The device for producing the nonwoven fabric is illustrated only schematically I FIG. 1. This means that the housings or frames that support the respective means or devices are not illustrated.

In FIGS. 2 and 3, the foulard 1 is illustrated in more detail. It can be seen that the first and the second roll rotate around a first and second roll axis 32, 34, respectively. The rolls 4, 2 are supported in a frame or housing, not illustrated herein.

The first roll 4 rotates in the sense of rotation 74 and the second roll 2 rotates in the sense of rotation 76. These two senses of rotation are opposite to each other. By rotating the first and second roll 4, 2, the gauze 14 is transported in the conveying direction 26.

The first roll 4 is an engraved roll. The roll sleeve of the first roll 4 has a groove-shaped engraving. As an alternative, the engraving may also be formed by a plurality of recesses formed in the roll sleeve and preferably being of frustoconical shape. The first roll sleeve is made of metal, preferably stainless steel. The groove-shaped engraving is formed in the first roll sleeve 8 preferably in a spiral shape.

The spiral-shaped or helical engraving is formed in the roll sleeve as a continuous recess in the form of a groove 44. Between the spiral-shaped or helical groove 44, a spiral-shaped or helical web 48 is provided, the web 48 having a surface 50 forming the surface of the roll sleeve 8. Alternatively, a plurality of grooves can be formed in the roll sleeve, which preferably extend along the circumference of the roll sleeve. As another alternative, a plurality of preferably frustoconical recesses can be formed in the roll sleeve.

When the roll sleeve 8 of the first roll 4 dives into the liquid binder 30 present in the trough 28, liquid binder 8 is taken along in particular in the engraving, i.e. in the case illustrated, in the groove 44, and is applied to the gauze 14. The dimensions of the engraving formed in the roll sleeve of the first roll are such that the volume of the region of the engraving that is in the nip region is greater than the volume of the binder present in the nip region.

Further, a stripping device 58 is provided. The stripping device 58 comprises a pivotable fastening element 62 pivotably mounted to the trough 28 or, as an alternative, to a frame. The pivotable fastening element 62 is pivotable around a pivot axis 64. The pivotable fastening element 62 is mounted with a stripping plate 60, in particular a doctor knife, and with a lever 66 at the respective ends. In this manner, the lever 66 can be used to manually guide the stripping plate 60 to the surface 50 of the roll sleeve 8, whereby the amount of binder 30 to be applied to the nonwoven can be controlled.

The second roll 2 and the first roll 4 are nip rolls. Relative to the gauze 14, 12, the second roll 2 is arranged on the side opposite the first roll 4. The first roll axis 32 of the first roll 4 and the second roll axis 34 of the second roll 2 are arranged vertically one above the other.

The second roll 2 has a roll sleeve 6. With a liquid foulard, the roll sleeve 6 is preferably made of synthetic material and in particular of rubber. The roll sleeve 6 of the second roll 2 is formed with a groove-shaped engraving. For this purpose, a groove 36 is provided in the roll sleeve 6 of the second roll 2. This groove 36 extends in a spiral or helical shape so that the same runs continuously around the second roll 2 in a spiral shape. Between the spiral-shaped groove 36, a spiral-shaped web 38 is provided, the web 38 being part of the roll sleeve 6. The web 38 has a surface 40 that forms the surface of the roll sleeve 6.

As an alternative, a plurality of grooves can be formed in the roll sleeve of the second rolls 2 instead of the single spiral-shaped groove. These can preferably extend substantially in the circumferential direction of the second rolls 2, and thus they can preferably extend in a plane that is substantially orthogonal to the roll axis 34 of the second roll 2.

When the gauze 14, 12 is squeezed, the binder 30 spread in the gauze 14, 12. When it is squeezed, the gauze, i.e. the fibers of the gauze, in the nip can escape into the engraving in the second roll 2. The volume of the engraving or the dimensions of the engraving in the roll sleeve 6 of the second roll 2 are such that the volume of that part of the engraving that is in the nip region is greater that the volume of the fibers of the gauze 14 that are in the nip region. In this manner, the fibers of the gauze 14 can escape into the engraving of the second rolls 2 so that no piling up of fibers of the gauze 14 or the binder occurs. Thus, the dimensions of the groove-shaped engraving in the roll sleeve 6 of the second roll 2 are such that the volume of the groove-shaped engraving that is in the region of the working width, is greater than the overall volume of the fiber gauze 14, 12 passing in operation between the first and the second roll 4, 2 per rotation of the second roll 2. The working width of the second roll 2 is the width of the gauze 14, 12 passing between the first and the second roll.

The open surface of the roll sleeve 6 of the second roll, which in the case illustrated corresponds to the surface of the spiral-shaped groove in the roll sleeve 6 on the plane of the surface 40 of the roll sleeve 6, preferably is between 60 and 98%, in particular between 80 and 85%. The closed surface of the roll sleeve 6 thus is the surface 40 of the web 30.

The width of the groove 36 or the grooves preferably tapers in the radial direction. The cross section of the groove 36 or the grooves preferably is frustoconical in shape.

As an alternative, the groove 36 or the grooves can also be notch-shaped, with the walls delimiting the groove 36 or the grooves extending in the radial direction, so that the open surface of the roll sleeve 6 remains constant even as the roll sleeve wears down.

The width of the groove 36 or the grooves of the second roll 2 in the plane of the surface 40 of the roll sleeve 6 preferably is between 0.3 and 2 mm, preferably between 0.5 and 1.5 mm, and, as is particularly preferred, is 1 mm. The open surface of the roll sleeve 6 of the second roll 2 and the width of the groove 36 or the grooves in the plane of the surface 40 of the roll sleeve 6 is chosen such that the nonwoven 12 to which the binder has been applied, does not adhere to the second roll 2. This is advantageous in particular at the outlet, since, due to the reduced adhesiveness, the gauze to which binder has been applied, does not stick on the second roll.

The second roll 2 has the further advantage that, owing to the groove 36 or the grooves, excess binder can also enter the groove 36 or grooves. The spiral shape of the groove further has the advantage that excess binder that has entered the groove 36 of the second roll 2 can drain easily.

The first and the second roll axis 32, 34, and thus the first and the second roll 4, 2, can be adjusted in the vertical direction so that the distance between the first and the second roll axis 32, 24 and the first and the second roll 4, 2 is adjustable. The webs 48, 38 and the groove 44, 36 or the grooves f the first and the second roll 4, 2 are arranged relative to each other such that the webs 48, 38 of the first and the second roll 4, 2, respectively, cannot enter the groove 44, 36 or the grooves of the first and the second roll 4, 2.

FIG. 4 illustrates an alternative embodiment of a device for producing a non-woven. Different from the device illustrated in FIG. 1, the foulard 1 shown is configured as a foam foulard. The rolls and the design of the roll sleeves 6, 8 correspond to those in FIGS. 1-3. However, different from the embodiment in FIGS. 1-3, the first and the second roll axis 32, 34 are arranged side by side in the horizontal direction.

The foam 72 is produced by means of a foam generator 70, with a binder 30 being supplied so that the foam 72 includes a binder 30. The foam 72 is applied to the gauze 14 and is passed through the two rolls 2, 4 together with the gauze 14 and the foam.

FIG. 5 shows a detail of the roll sleeve 6 of the second roll 2. A part of the groove-shaped engraving formed in the roll sleeve 6 is visible. The groove 36 has a sectional area A. In the plane of the surface 40 of the roll sleeve 6, the groove 36 has a width B. The width B preferably is between 0.1 and 2 mm, preferably between 0.5 and 1.5 mm, particularly preferred 1 mm.

The width of the groove 36 tapers in the radial direction. The groove 36 has a depth t. The groove 36 has a width x at the deepest point. The cross section of the groove 36 is frustoconical. The web 38 has a width s. The width s of the web 38 is preferably between 0.1 and 2 mm, preferably between 0.5 and 1.5 mm, particularly preferred 1 mm.

The width between two web centers is identified as L. The area A1 is the area between two web centers multiplied with the depth t of the groove. The ratio of the sectional area of the groove A and the area A1 preferably is between 20 and 70%, in particular between 35 and 55%, particularly preferred between 40 and 45%.

In the schematic FIGS. 6 a to 6 c, different shapes of cross sections of the groove-shaped engraving formed in the roll sleeve of the second rolls are illustrated. FIG. 6 a shows a conical section. FIG. 6 b shows a notch-shaped section and FIG. 6 c shows a semicircular section.

In this foulard, the groove-shaped engraving of the second roll and the groove-shaped engraving of the first roll are arranged offset with respect to each other preferably in the axial direction of the rolls such that the web or the webs of the second roll cannot engage the groove or grooves of the first roll and the web or the webs of the first roll cannot engage the groove or the grooves of the second roll. 

1. A foulard for applying a binder to a gauze, nonwoven or preliminary nonwoven, comprising at least a first roll rotatable around a first roll axis, said roll having a roll sleeve provided with an engraving, at least a second roll rotatable around a second roll axis, said roll having a roll sleeve, and wherein the gauze, nonwoven or preliminary nonwoven runs between the first and the second roll, wherein the roll sleeve of the second roll comprises at least one engraving.
 2. The foulard of claim 1, wherein the engraving in the roll sleeve of the second roll is at least a groove-shaped, preferably spiral-shaped engraving.
 3. The foulard of claim 1, wherein the dimensions of the at least one, preferably groove-shaped engraving in the roll sleeve of the second sleeve are such that the volume of the preferably groove-shaped engraving is larger than the overall volume of the gauze, nonwoven or preliminary nonwoven, consisting of fibers, which in operation passes between the first and second roll per rotation of the second roll.
 4. The foulard of claim 1, wherein the dimensions of the at least one preferably groove-shaped engraving are such that the open area of the surface of the roll sleeve of the second roll preferably is between 60 and 98%, in particular between 80 and 85%.
 5. The foulard of claim 2, wherein the width of the groove-shaped engraving in the surface of the roll sleeve of the second roll is between 0.1 and 2 mm, preferably between 0.5 and 1.5 mm, and in particular 1 mm.
 6. The foulard of claim 2, wherein the width of the groove-shaped engraving in the roll sleeve of the second roll tapers in the radial direction.
 7. The foulard of claim 2, wherein the cross section of the groove-shaped engraving in the roll sleeve of the second roll is conical, frustoconical, notch-shaped or semicircular.
 8. The foulard of claim 1, wherein the roll sleeve of the second roll is made of synthetic material, preferably of rubber.
 9. The foulard of claim 1, wherein the roll sleeve of the second roll is made of metal.
 10. The foulard of claim 1, wherein the engraving in the first roll is at least a groove-shaped, preferably a spiral-shaped engraving or is formed by a plurality of preferably frustoconical or pyramidal recesses formed in the roll sleeve of the first sleeve.
 11. The foulard of claim 1, wherein the first roll is arranged such that the roll sleeve of the first roll plunges at least partly into a trough filled with a liquid binder, so that the liquid binder can be applied to the nonwoven or the gauze by means of the first roll.
 12. The foulard of claim 1, wherein a binder dissolved in foam can be applied to the gauze.
 13. A method for applying a binder for a gauze, nonwoven or preliminary nonwoven, by feeding a gauze, nonwoven or preliminary nonwoven to a foulard having a first and a second roll, the roll sleeves of the first and the second roll comprising at least one engraving, applying the binder to the gauze, nonwoven or preliminary nonwoven, passing the gauze, nonwoven or preliminary nonwoven through the first and the second roll, applying pressure on the gauze, nonwoven or preliminary nonwoven via the roll sleeves of the rolls.
 14. The method of claim 13, characterized in that a liquid binder is applied to the gauze, nonwoven or preliminary nonwoven.
 15. The method of claim 13, wherein a binder dissolved in foam is applied.
 16. The method of claim 14, wherein a binder dissolved in foam is applied.
 17. The foulard of claim 2, wherein the dimensions of the at least one, preferably groove-shaped engraving in the roll sleeve of the second sleeve are such that the volume of the preferably groove-shaped engraving is larger than the overall volume of the gauze, nonwoven or preliminary nonwoven, consisting of fibers, which in operation passes between the first and second roll per rotation of the second roll. 